I just bought a set of 3/4 ton axles from a 77 K20 to go into my blazer. The diifferentials have a little bit of grit and a couple of tiny surface rust stops in the differentials. I know thats not good, but its what i got and these are hard to come by around here. What method, and cleaners should i use to try and wash out the differentials while they are still assembled? Would brake cleaner be ok or will that damage any seals?